Thickened butyrolactone-based nail polish remover with applicator

ABSTRACT

A thickened nail polish-lacquer removing composition having a smooth, substantially non-granular consistency. The composition is substantially non-irritating and non-sensitizing to the skin surrounding the fingernails and toenails. Upon drying, the residue of the lacquer-removing composition is water-soluble. The composition includes from 51% to 99.9% by weight of butyrolactone organic solvent and/or a propylene glycol derivative solvent and from 0.1% to 5% by weight of at least one water-soluble thickening agent capable of functioning in the absence of a neutralizing agent, and which is present in an amount effective to produce an absolute kinematic viscosity at 20° C. of from 250-10,000 cp.

RELATED APPLICATION

[0001] This application is a continuation-in-part of Perlman, U.S.patent application Ser. No. 09/144,189, filed Aug. 31, 1998, entitledTHICKENED PROPYLENE GLYCOL ETHER NAIL POLISH REMOVER, which is herebyincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to the field of cosmetics products,specifically to the field of liquid nail polish removers.

[0004] 2. Background

[0005] The following description is provided solely to assist theunderstanding of the reader. None of the references cited are admittedto be prior art to the present invention.

[0006] Organic solvent-based products have been marketed for many yearsfor removing nail polishes from fingernails and toenails. In recentyears, water-based nail polishes have also emerged, and are removedusing similar solvent-containing products. For reasons of economy andefficacy, the most common solvent systems used to remove such nailpolishes (also known as lacquers) have been acetone and ethyl acetate.However, many problems including skin irritation, and skin and cuticledesiccation are associated with the use of these solvents, and manypatents have been issued to remediate these problems.

[0007] For example, Curtis (U.S. Pat. No. 4,485,037) describes anaqueous acetone-based nail polish remover whose tendency to remove waterfrom the fingernail and skin is reduced by incorporating an amine saltof a fatty acid amide of a hydrolyzed collagen, and a fattyacid-substituted trialkylamine cationic surfactant. Hofmann (U.S. Pat.No. 4,824,662) describes an acetone or ethyl acetate solvent-based nailpolish remover containing a surfactant and an amidoamine salt ofhydrolyzed soy protein to reduce the skin and nail water removalproperties of the solvent. Hofmann (U.S. Pat. No. 5,077,038) alsodescribes an acetone and/or ethyl acetate-based nail polish remover inwhich the solvent concentration is limited to approximately 60-80% byweight, and water is added (approximately 20-40% by weight). The salt ofa hydrolyzed soy protein and cocamidopropyl dimethylamine propionate areadded to prevent drying of the nail and surrounding skin.

[0008] Helioff et al. (U.S. Pat. No. 5,024,779) describe a creamyviscous nail polish remover based upon acetone, methyl ethyl ketone,ethyl acetate, and/or butyrolactone, and containing up to about 3% byweight of neutralized crosslinked maleic anhydride-alkyl vinyl ethercopolymer gel, and a humectant. Day (U.S. Pat. No. 4,804,486) describesa cream-like nail polish remover utilizing gamma-butyrolactone solvent,and a neutralized acrylic acid-type gelling agent. Remz et al. (U.S.Pat. No. 5,294,435) describe an acetone-based nail polish removercontaining a conditioning agent, e.g., stearic acid and triethanolamine,and a suspending agent, e.g., styrene methacrylic polymer, to avoidprecipitation of the conditioner. Miner et al. (U.S. Pat. No. 5,342,536)describe an acetone-based nail polish remover that includes gelatin andalso glycerin to hold the gelatin in suspension. Faryniarz et al. (U.S.Pat. No. 5,486,305) describe an acetone and/or ethyl acetate-based nailpolish remover which contains a diester compound, and a humectant andemollient for conditioning the cuticle and nails. Appell (U.S. Pat. No.5,027,839) describes a device to protect the skin from irritation causedby these nail polish remover solvents.

[0009] Solvent systems other than acetone and ethyl acetate have beendescribed in the patent literature for nail polish lacquer removers, buthave met with limited commercial success. These alternative systems havedistinct drawbacks including health risks and environmental toxicityproblems. For example, Adams (U.S. Pat. No. 4,543,206) describes anon-flammable methylene chloride-based liquid solvent system. There is ahealth risk associated with inhalation of methylene chloride, andenvironmental disposal of chlorinated hydrocarbons poses a problem.Dotolo et al. (U.S. Pat. No. 5,346,652) describe a non-aqueousfingernail polish remover based upon a d-limonene, N-methyl pyrrolidone(abbreviated NMP), and cetyl acetate solvent system. However, d-limoneneis harmful if swallowed, can be irritating, causes drying, reddening,and sensitization of the skin, and is moderately to highly irritating tothe eyes (MSDS, d-limonene, Florida Chemical Co., Inc., Winter Haven,Fla.). Moreover, NMP is now listed an environmentally contaminatingtoxic solvent under the U.S. Environmental Protection Agency(abbreviated EPA) regulations, and is so-listed (SARA Title III, sec.313). Similarly, Bayless (U.S. Pat. No. 5,372,742) describes anon-aqueous liquid cleaner suited for removing nail polish, based upond-limonene, ethyl lactate, and cetyl acetate.

[0010] Several patents have focussed on thickener or gelling systems fornail polish lacquer removers. For example, Minton et al. (U.S. Pat. No.4,197,212) describe an acetone or ethyl acetate-based nail polishremover which contains a hydroxypropyl cellulose acetate gelling agentwhich provides a Brookfield viscosity of 1,000 to 10,000 cp, and whichleaves a beneficial residual film on the nail. Miner (U.S. Pat. No.5,543,085) describes a thickened laquer-remover such as acetone-ethylacetate thickened with an acrylate/vinyl acetate polymer, in which anelectrolyte is added to the formulation to avoid a slimy or tackyresidue on the nail and finger upon solvent evaporation.

[0011] As discussed above, several non-acetone/ethyl acetate organicsolvents, including chlorinated hydrocarbons, N-methylpyrrolidone (NMP),and d-limonene, have been previously suggested for use in nail polishremovers. However, these solvents have been either listed as pollutantson the HAP and/or SARA lists of the EPA, or have been implicated astoxic substances, respiratory irritants, skin irritants, or skinsensitizers, and consequently are relatively undesirable for use inconsumer products. While the common EPA-unlisted solvents includingacetone and ethyl acetate are currently used in most nail polish removerproducts, they are undesirable for several reasons including theirunpleasant smell, their vapors being irritating to the eyes, theirexcessive volatility, and their being desiccating and irritating to thecuticle and skin around the nail. Acetone is also known to causebronchial irritation, and skin erythema via topical exposure.

[0012] Among recent patents for nail polish removing compositions, thefollowing are typical of compositions which utilize acetone or ethylacetate as the primary active solvent: U.S. Pat. Nos. 5,543,085 byMiner, 5,486,305 by Faryniarz et al., 5,342,536 by Miner et al.,5,294,435 by Remz et al., 5,024,779 by Helioff et al., 5,077,038 byHofmann, 4,824,662 by Hofmann, 4,485,037 by Curtis, and 4,197,212 byMinton et al.

SUMMARY OF THE INVENTION

[0013] This invention concerns a substantially non-volatile Liquid NailPolish Remover (abbreviated LNPR) based upon the organic solvent, gammabutyrolactone (abbreviated GBL) and/or propylene glycol ether solvents,and to devices, compositions and methods for utilizing the solventsafely, practically and cost-effectively. Compared to conventionalsolvents, acetone and ethyl acetate, GBL is very costly. However, itslow volatility allows very small (and thus cost-effective) quantities ofthe solvent to be applied, and to persist and dissolve nail lacquer onthe surface of a fingernail or toenail. A reusable dip-applicatordevice, such as a small brush located in the lid of the LNPR container,is used for withdrawing and applying microliter quantities of the LNPRto nails. This highly efficient method of applying GBL does not workwith highly volatile solvents, such as acetone and ethyl acetate, whichevaporate before they can dissolve a lacquer coating. With acetone andethyl acetate, generally a saturating volume of the solvent must beinstilled into an absorbent pad or cotton ball which is then rubbed backand forth over a nail until a lacquer dissolves. Such a volume iscommonly 0.2-0.5 ml or even more.

[0014] The present invention also concerns the coordinate use of solventthickener with GBL. By placing the GBL solvent (preferably thickened) ina narrow-necked bottle, the GBL is accessible by dip-applicator, but isrendered more resistant to misuse, e.g., ingestion by children. Thethickener is preferably pH-stable (i.e., chemically stable andfunctionally tolerant to changes in pH) so that the LNPR will remainthickened, even as its pH of the solution changes over its lifetime.

[0015] A method has also been found for treating and improving acellulosic thickener (hydroxypropylcellulose) which has been dispersedin GBL. The normally granular-textured cellulosic dispersion is shearedto produce a smooth-textured thickened GBL solution. The resultingsolution can then be treated, e.g., filtered and/or centrifuged, toremove residual large clumps. Alternatively, the clumps can be removedby centrifugation or filtering alone.

[0016] In preferred embodiments, the LNPR and its dried residue arewater-soluble, biodegradable, and its vapors are not irritating to theeyes. As stated above, in contrast to acetone and ethyl acetate-basedremovers, the GBL-based LNPR is substantially non-volatile (unlessvolatile liquids, e.g., co-solvents, are added), causes little drying ofthe skin around the nail, and causes no skin irritation or sensitizationupon repeated application, even in the absence of any humectant oremollient. Moreover, in the absence of an electrolyte, the removercomposition leaves no gummy or sticky residue after solvent evaporation,or after wiping the nail polish/solvent residue from the nail.Furthermore, the remover composition is especially useful for looseningand removing hard-to-remove so-called “glitter” nail lacquers whichcontain suspended flecks of solvent-inert material such as polyesterfilm.

[0017] Thus, in a first aspect, the invention provides a safety-enhancedpackaged liquid nail polish-lacquer removing composition. Thecomposition includes a nail polish-lacquer removing solution which isnon-irritating and non-sensitizing to the skin surrounding nails. Theremover includes between 51% and 100% by weight of thickenedbutyrolactone solvent, preferably from 70% to 99.9%, more preferablyfrom 80% to 99.9%, packaged in a narrow-necked container, with thenarrow neck of the container serving to retard or block the flow ofsolution out of the container when the container is tipped on its sideor inverted. There is a maximum of 100 ml (or 3 fluid ounces) of thesolution in the container. The composition also includes a reusableapplicator device for applying microliter quantities of the solution toeach nail.

[0018] As small volumes enhance the safety by reducing the overalltoxicity hazard of ingestion, preferably there is a maximum of 30 ml (or1 fluid ounce) of the solution in the container.

[0019] In preferred embodiments, the applicator device is an applicatorbrush, porous foam swab or pad, a hollow tube, an eye dropper, a dipstick or a combination of those devices. In preferred embodiments, thereusable applicator device is attached to a lid which covers thecontainer.

[0020] In preferred embodiments, the solution contains at least onethickening agent present in an amount effective to produce an absolutekinematic viscosity at 20° C. of from 250-10,000 cp, preferably from1000-10,000 cp, more preferably from 2000-8000 cp. Preferably thethickening agent functions in the absence of a neutralizing agent,preferably providing thickening over a pH range of at least pH 5-9, morepreferably 4-9, or 5-10, or 4-10.

[0021] To further enhance safety by reducing the danger of ingestion, inpreferred embodiments the solution also contains a bittering agent.

[0022] In addition, as the composition is adapted for repetitive use,such that an applicator will be contacted to a fingernail or toenailmany times during use of a container of remover, it is preferable thatthe remover resists growth of microbes (e.g., bacteria and/or fungi) andstill more preferably kills any microbes carried into the container.Thus, preferably the solution in this and the following aspects does notcontain a substantial concentration of water, preferably the watercontent is less than 5% by weight, more preferably less than 2%, andmost preferably less than 1%. Advantageously the remover solution isformulated without water (though there may still be a small amount ofwater absorbed from the atmosphere).

[0023] Also in view of the repetitive use, which can carry microbes intoa container of the remover, one or more antimicrobial agents, e.g.,antibacterial agents, can advantageously be included in the removersolution or composition of this and/or following aspects. For example,methylparaben and propylparaben (e.g., as specified in Day, supra) canbe used. Preferred concentrations so of these agents are from 0.15 to0.3% by weight total, with the methylparaben at approximately twice theconcentration of the propylparaben (e.g., 0.2% and 0.1% by weightrespectively). Other antibacterial and/or antifungal agents can also beused as recognized by those skilled in the art.

[0024] Additional embodiments are as described for the aspect below. Thesolution may contain additional components as described for nailpolish-lacquer removing compositions below.

[0025] In related aspects, the solution and its components, especiallythe solvent and thickening components of the solution, are as describedfor other aspects herein.

[0026] The term “nail polish-lacquer” refers to materials commonly usedfor providing a protective and/or visual coating on fingernails and/ortoenails, including materials referred to as nail polish, nailpolish-lacquer, nail enamel, and similar names.

[0027] The term “butyrolactone” refers to a four carbon lactone, whichis thus a four carbon cyclic ester. Highly preferred is gammabutyrolactone, which is also known by the names dihydro-2(3H)-furanone,and 4-butyrolactone.

[0028] Indication that a nail polish-lacquer remover or a thickener inthe polish remover is “tolerant to pH changes” or “pH stable” means thatthe thickening persists over at least a 3 pH unit range, preferably atleast 4 pH units, and more preferably at least 5 pH units, or thethickening persists over the range of pH changes occurring duringrepeated use of a packaged container of the remover with reuse of anapplicator which carries nail polish residue into the polish removerreservoir. The persistence of thickening occurs without the presence ofa neutralizing agent (e.g., neutralizing agents as described in Helioffet al., supra and Day, supra) or pH buffer (though such neutralizers orbuffers may be present) Indication that a thickener is “effectivewithout neutralization” means that the thickening is effective withoutthe presence of a neutralizing agent (e.g., neutralizing agents asdescribed in Helioff et al., supra and Day, supra) or pH buffer (thoughsuch neutralizers or buffers may be present) under conditions where thethickeners described in Helioff et al. and Day would not retain adequatethickening in the absence of the neutralizers, e.g., as describedtherein, or effective pH buffering. Preferably the thickener is“effective in the absence of a neutralizer” over a range of at least 3pH units, more preferably at least 4 pH units, and still more preferablyat least 5 pH units.

[0029] In another aspect, the invention provides a nail polish-lacquerremoving composition which includes from 51% to 99.9% of GBL, preferablyfrom 70% to 99.9%, more preferably from 80% to 99.9% and at least onethickening agent which is present in an amount effective to produce anabsolute kinematic viscosity at 20° C. of from 250 to 10,000 cp,preferably from 1000 to 10,000, more preferably from 2000 to 8,000. Thethickening agent is pH stable, thus can withstand changes in pH in theLNPR preferably at least between pH 5 and 9, more preferably between pH4 and 9, or 5 and 10, or 4 and 10 while maintaining thickening asspecified.

[0030] In a related aspect, the invention provides a nail polish-lacquerremoving composition which includes from 51% to 99.9% of GBL, preferablyfrom 70% to 99.9%, more preferably from 80% to 99.9% and at least onethickening agent which is present in an amount effective to produce anabsolute kinematic viscosity at 20° C. of from 250 to 10,000 cp,preferably from 1000 to 10,000, more preferably from 2000 to 8,000. Thethickening agent is not neutralized crosslinked maleic anhydride-alkylvinyl ether copolymer gel (e.g., not neutralized crosslinked maleicanhydride-C₁-C₄ alkyl vinyl ether copolymer gel) or a neutralizedacrylic acid polymer (e.g., neutralized with a neutralizer containingN,N,N′,N′-tetrakis (2-hydroxypropyl)ethylaminediamine and2-ethyl-N-(2-ethylhexyl-1-hexamine) Preferably the thickening agent canwithstand changes in pH in the LNPR at least between pH 5 and 9, morepreferably between pH 4 and 9, or 5 and 10, or 4 and 10.

[0031] The compositions of the above aspects can also optionally includea humectant/diluent. A humectant/diluent is preferably present in anamount sufficient to enhance moisture retention in a surface to whichthe composition is applied, but not so high as to prevent thecomposition from being effective to remove nail polish, usually up 20%by weight of the composition. An acceptable maximum for ahumectant/diluent will depend, in large part, on the selection ofsolvent compounds and the effects of the humectant/diluent or othercomponents on the solvent activity, and can be readily adjusted to anappropriate level.

[0032] Independently, the composition can optionally contain anemollient, which preferably is present in an amount sufficient toenhance moistening of a surface, e.g., skin, with which the compositioncomes into contact, usually up to 10% by weight. An emollient should notbe present in such a large concentration as to prevent the compositionfrom functioning as a nail polish remover. Also preferably an emollientis not present in such a large concentration as to leave an undesirablecoating on skin or nail after the composition is wiped away.

[0033] In the present invention, a solvent thickener which is combinedwith GBL serves at least two distinct functions. First, the thickenerreduces solvent “runniness”, thereby helping localize the LNPR on thenail. In fact, when a small dip-applicator device such as a brush orhollow stick applicator is used to transfer the thickened LNPR onto anail, it has been found that as little as 10-50 microliters of thethickened GBL-based LNPR can be used to fully coat a nail and remove thenail lacquer. Second, when the LNPR is packaged in a narrow-neckedcontainer (e.g., a container having approximately a 4 mm-10 mm diameteropening) the presence of thickener helps the composition form an airlockin the container, reducing or preferably blocking the outflow of LNPRwhen the container is tipped onto its side or inverted. This featurehelps to control misuse of the GBL-containing composition, e.g., helpsto prevent a child from ingesting the LNPR, or spilling the LNPR andcontacting his eyes, causing eye irritation. A substantiallypH-insensitive of pH stable thickener (e.g., a thickener effective overa pH range as indicated) is preferably used so that an elevatedviscosity can be maintained, even as the pH of the remover maysubstantially change over the lifetime of the product. For example, abrush applicator used with the LNPR, and which carries contaminants fromlacquer-coated nails back into the LNPR container may cause an upward ordownward pH change over a pH range of at least 5-9.

[0034] The GBL-containing compositions of the invention can also besupplemented with other types of solvent compounds, i.e., co-solvents,such as a propylene glycol-derivative solvent consisting of at least onecompound which is a propylene glycol ether, a dipropylene glycol ether,a propylene glycol ether ester, or a dipropylene glycol ether ester. Inpreferred embodiments, propylene glycol derivative co-solvents includeat least one of the exemplary compounds: propylene glycol methyl ether(PM; 1-methoxy-2-propanol, CAS No. 107-98-2), propylene glycol methylether acetate (PMA; 1-methoxy-2-propanol acetate, CAS No. 108-65-6),dipropylene glycol monomethyl ether (DPM; CAS No. 34590-94-8),dipropylene glycol methyl ether acetate (DPMA; CAS No. 88917-22-0),propylene glycol ethyl ether (PE; CAS No. 52125-53-8), propylene glycolethyl ether acetate (PEA; CAS No. 98516-30-4), propylene glycol n-propylether (PNP; CAS No. 1569-01-3), propylene glycol t-butyl ether (PTB; CASNo. 57018-52-7), propylene glycol n-butyl ether (PNB; CAS No.5131-66-8), and dipropylene glycol n-propyl ether (DPNP, CAS No.29911-27-1).

[0035] As indicated above and further described below, the compositionsmay contain one or more other solvents, i.e., co-solvents. These othersolvents may provide a variety of functions depending on the specificsolvent chosen. For example, the co-solvent may function as one or moreof diluent, humectant, active co-solvent, solubilizing agent for anothercomponent (e.g., a thickening agent). Preferred examples of suchco-solvents include propylene glycol, lower alcohols (generally 1, 2, 3,or 4 carbon atoms, e.g., ethanol and isopropanol), along with othersdescribed herein. While their use may introduce some level of skinirritation, the conventional nail polish remover solvents, acetone andethyl acetate can also be used as co-solvents if desired, e.g., toprovide a highly active secondary solvent. Preferably, if used, theacetone and/or ethyl acetate is used at a low percentage, e.g.,preferably equal to or less than 30%, and more preferably equal to orless than 20% or 10% or 5%.

[0036] The thickening agent is preferably present in the composition inan amount sufficient to allow the composition to provide a layer thickerthan a mere liquid film layer when applied to a fingernail or toenail. Avariety of different thickeners may beneficially be used, and acombination of thickeners may also be used if desired. In order toprovide appropriate thickening characteristics, preferably thethickening agent or agents is present in an amount from 0.1% to 5% byweight, more preferably from 0.2% to 3%, still more preferably from 0.2%to 1%, of the composition. Preferably, a thickening agent is a cellulosederivative, a natural gum, an inorganic thickener, or a synthetichomopolymer or copolymer having from 1 to 30 carbon atoms per monomerunit. Preferred examples of cellulose derivatives includehydroxycellulose, hydroxyalkylcellulose, and carboxymethylcelluose, morepreferably hydroxyethylcellulose, hydroxypropylcellulose, andhydroxypropylmethylcellulose. Preferred examples of synthetichomopolymers or copolymers are polyacrylic acid esters, polymethacrylicacid esters, polyvinylacetate, and polyvinylpyrrolidone. Preferredexamples of natural gums are acacia, alginate, carrageenan, guar,karaya, pectin, tragacanth, and xanthan. Preferred examples of inorganicthickeners are silicas and clays.

[0037] As indicated above, the composition may optionally contain atleast one humectant/diluent. Preferred examples of suitablehumectants/diluents include water, glycerol, propylene glycol,1,3-butylene glycol and its isomers, sorbitol and combinations thereof.

[0038] Also as indicated above, independently the composition mayoptionally contain at least one emollient. Preferred examples of suchemollients include fatty acid esters, mineral oil, silicone oil,lanolin, lanolin derivatives and combinations thereof.

[0039] As described above, use of the propylene glycol derivativeco-solvents provides certain advantages over other commonly usedsolvents in LNPRs such as acetone and ethyl acetate. For example, thenail polish-lacquer removing composition, upon removal, allows thefingernails and toenails to remain substantially free of any stickyresidue, without addition of any electrolyte to the composition.Further, the vapors from the propylene glycol derivative co-solvent, aswell as from the composition as a whole are preferably substantiallynon-irritating to the eyes. Also, the propylene glycol derivativeco-solvent, and preferably the GBL-containing composition as a whole, issubstantially non-irritating and non-sensitizing to the skin surroundingfingernails and toenails when used to remove nail polish-lacquer. Thelatter in vivo findings are important because erythema is a significantskin problem associated with the use of acetone-based remover products.Regardless of whether a humectant and/or an emollient were present, PMand PMA as co-solvents were much gentler to the skin than acetone,causing no visible irritation or reddening

[0040] In the context of the effect of nail polish removers on humanskin, the terms “non-irritating” and “non-sensitizing” mean that thesolvent or composition referenced causes visibly less skin irritation,e.g., skin reddening or erythema, than acetone or ethyl acetate on equalexposure under conditions where acetone or ethyl acetate cause visibleskin changes (e.g., initial whitening and drying, and subsequent skinreddening). In reference to the effects of a solvent on the eyes, theterm “non-irritating” means that normal exposure of the eyes to solventvapors during the removal of nail polish does not result in any visiblereddening or discomfort to the eyes or the immediately surroundingtissues.

[0041] Many of the propylene glycol derivative co-solvent compounds havepronounced ether and ester-type odors. If desired, those solvent odorscan be masked, such as by using any one of a number of top notefragrances (e.g., citrus, cherry and other fruit fragrances), which havebeen successfully used as maskers of these such ether and ester odors inother applications. Thus, such a fragrance may also be included in thecomposition.

[0042] While the thickened, GBL-containing solvent-based nail polishremover composition provides advantages as briefly described above, suchas being non-irritating and non-sensitizing, and further can be moreconvenient to use due to its low volatility and consequent slowevaporation, in some cases it may be desired to add a more volatilesolvent component to a GBL-based polish remover. For example, it may bedesired to add a more volatile solvent as a co-solvent in order toprovide a more active total solvent. Therefore, even a solvent such asacetone or ethyl acetate, can be added to the composition, but in suchpreparations, the co-solvent component is present at levelssubstantially below those which would be used if the co-solvent were theprincipal solvent component in a nail polish remover. Thus, preferablythe co-solvent component or components is present at, or less than thepercentage which would be used if the co-solvent were the principalsolvent in a nail polish remover. Preferably, the co-solvent is presentat 40% or less by weight of the composition, more preferably 30% orless, still more preferably 20% or less, and most preferably 10% or 5%or less. Preferably, the addition of one or more co-solvent compoundsalongside of GBL does not cause the composition to become irritating orsensitizing to the skin or the vapors irritating to the eyes of a user.Preferably the addition of such a solvent component increases thesolvent activity of the composition toward a nail polish.

[0043] In another aspect, the invention provides a nail polish-lacquerremoving composition which includes butyrolactone solvent and/or apropylene glycol derivative solvent, where the butyrolactone andpropylene glycol derivative solvents together are 51-99.9% by weight,preferably 70-99.9%, more preferably 80-99.9%, of the total nailpolish-lacquer removing composition. Preferably both butyrolactone and apropylene glycol derivative solvent are present. Preferably thebutyrolactone concentration is greater than the propylene glycolderivative solvent concentration.

[0044] As described for compositions above, other co-solvents may alsobe present if desired.

[0045] Additional embodiments are as described for nail polish-lacquerremoving compositions described above and in the following DetailedDescription.

[0046] In a related aspect, the invention provides a method of removinga nail polish-lacquer coating from a fingernail or toenail withoutcausing irritation of the skin surrounding the nail using a nail polishremoving composition as described above. The nail polish-lacquer can bea pigmented lacquer, a glitter-containing lacquer, or some other noveltylacquer which may be produced by the cosmetics industry from time totime. The method includes the steps of:

[0047] (i) applying the nail polish-lacquer remover compositiondescribed above to the coating on the fingernail or toenail;

[0048] (ii) allowing the coated fingernail or toenail and the removercomposition to remain in contact for a time sufficient to loosen thecoating from the fingernail or toenail, and

[0049] (iii) separating and removing the coating and the removercomposition from the fingernail or toenail.

[0050] The steps may be repeated as needed to accomplish full removal ofthe coating from the nail.

[0051] As previously discussed, application of the composition maypreferably be accomplished using any convenient dipping-type applicatorsuch as a brush or swab-type applicator, for example. It is preferredthat the applicator is integrated into the lid of the container holdingthe LNPR. For example, a small applicator brush on a shaft can beattached to a screw cap lid, and extend downward into the LNPR, muchlike a nail polish applicator brush extends downward into a bottle ofnail polish.

[0052] The time required for softening and loosening a nail lacquercoating in vivo varies with the choice of solvent or solvents describedherein, and the presence or absence of any co-solvent, diluent,humectant, emollient and the like, as well as the particular type ofnail polish. Typically however, waiting about 15 seconds afterapplication before wiping the coating and remover composition from thenail is adequate. The time range presently considered practical for thisdelay between application and removal is between approximately 10seconds and 2 minutes. A paper tissue or absorbent paper towel or anabsorbent fiber ball, such as a cotton ball, may be convenientlyemployed for wiping away, i.e., separating and removing, the nail polishand remover composition from the fingernail or toenail.

[0053] In preferred embodiments, the composition is as described inembodiments of aspects above, e.g., including preferred packaging in anarrow-necked bottle.

[0054] The examples described below will illustrate and compare the invitro effectiveness of GBL and a variety of propylene glycol-derivativeco-solvents in softening and releasing a conventional nail polish.

[0055] In connection with the use of the present nail polishlacquer-removing compositions, the term “a time sufficient to loosen thecoating from the fingernail or toenail” means a time sufficient so thata substantial portion of the coating under remover composition issufficiently loosened so that it can be wiped away, but not so long thatthe remover composition dries sufficiently that the remover compositioncannot be fully wiped away. The phrase “loosen the coating from thefingernail or toenail” refers to a process of partially or fullysoftening or dissolving the nail polish coating, or loosening theadhesion of the coating to the nail, or combinations of those effects.The phrase “separating and removing the coating and the removercomposition” refers to a process of removing at least a portion of thenail polish, e.g., by wiping away with an absorbent fiber ball. Highlypreferably, at least most of the nail polish from the nail being treatedis removed in a single treatment, preferably such that only a clean-uptreatment or no further polish removal treatment is needed.

[0056] In a further aspect, the invention provides a method of treatinga granular suspension of between 0.1% and 5% by weighthydroxypropylcellulose, preferably between 0.25% and 1%, contained in aliquid comprising between 51% and 99.9% by weight butyrolactone, toproduce a smooth-textured thickened solution. The method involvesremoving a sufficient proportion of granular material from thesuspension to provide the smooth-textured thickened solution. Thegranular material can be removed in a variety of different ways,including, for example, shearing, filtering, or centrifuging thesuspension, or using two or more of those techniques in combination.Thus, in preferred embodiments, the suspension is sheared and filtered;the suspension is centrifuged; the suspension is sheared andcentrifuged; the suspension is filtered.

[0057] In the context of this invention, the term “propyleneglycol-derivative solvent or co-solvent” refers to a compound or mixtureof compounds which is liquid at room temperature and in which thecompound or compounds can be viewed as chemical derivatives of propyleneglycol with the addition or substitution of one or more substituentgroups, generally substituting on the hydroxyl groups. The substituentgroups do not cause the solvent compound to become irritating to theskin or toxic. In order to provide sufficient volatility, the solventcompounds are limited to those having one or two propylene glycolmonomer units. A limited amount of larger molecules, such astripropylene glycol methyl ether or other derivative could also be usedin combination. The substituents are preferably hydrocarbon orcarboxylate groups having 1, 2, 3, or 4 carbon atoms and/or, morepreferably 1 to 3, and most preferably 1 to 2 carbon atoms, thus formingethers and/or esters. Preferably the hydrocarbon group is an alkylgroup. As indicated above, preferably a derivative is an alkyl ether oralkyl ether ester derivative

[0058] In connection with the concentrations of the various componentsin the described compositions, the ranges of percentages include the endpoints. For example, a range of 70 to 99.9 weight %, or 70-99.9 weight%, for a component A, means that the compositions can include 70% or 90%or any other concentration of component A within those endpoints, butincluding the endpoints. Also in this context, a “wt. %” or “weight %”or “weight percent” or “percent by weight” refers to the conventionalcalculation of weight percent, that is:

wt. % of component A=[(weight of component A in composition)÷ (totalweight of composition)]×100.

[0059] The term “thickening agent” refers to a compound or combinationof compounds which acts to increase the viscosity of a liquid solutionor suspension. Preferably a thickening agent is not present in such alarge amount as to result in solidification of the composition. It ishighly desirable that the composition remain able to be smoothly appliedon a nail and/or to flow slowly. Thus, the presence of a thickeningagent preferably results in partial thickening or partial gelling,resulting in a viscous liquid.

[0060] The term “humectant/diluent” as commonly used in connection withskin care products and as used herein, refers to a compound or compoundswhich acts to enhance moistening or moisture retention, e.g., by humanskin and tissue, and/or dilute the solvent in a composition asdescribed. Preferably, one compound performs both functions. Whileusually one compound will be provided as a “humectant/diluent”, morethan one compound can be utilized in combination, and such multiplecompounds is included in the term “humectant/diluent”.

[0061] The term “emollient” is used in its usual skin care sense,referring to a material which promotes softening of a material to whichit is applied, e.g., human skin. While usually one compound would beused in the present compositions as an emollient, more than one compoundcan be used, and such multiple compounds are included in the term“emollient”. Those skilled in the art are familiar with a variety ofcompounds suitable for this purpose and their appropriate usage.

[0062] The terms “narrow neck(ed)” refers to the upper portion,including the container opening, of a container such as a bottle used tohold the nail polish remover, and more specifically to the innerdiameter or width of the container opening which provides access to theliquid contents. Preferably, this diameter is between 3 mm and 10 mm(endpoints included), more preferably between 4 mm and 10 mm or 4 mm and7 mm.

[0063] In connection with flow of contents from a narrow-necked bottleor container, the term “retard” or “reducing” indicates that the outflowfrom a normally filled container or bottle at normal room temperaturesis much slower than from a bottle of similar capacity and similarinternal dimension in the lower portion of the bottle but which does nothave an opening or neck which retards flow. Preferably the outflow isnot a continuous stream when the bottle or container is tipped at 90degrees or inverted. Preferably, the outflow of ½ of the contents of anarrow-necked bottle requires at least twice as long (2×), morepreferably at least 5 times as long (5×), still more preferably at least10 times as long (10×) as the outflow of ½ of the same volume from astraight-sided glass beaker. Preferably the outflow stops completelyprior to the outflow of ½ or ¼ of the contents of the narrow-neckedcontainer or bottle.

[0064] The term “bittering agent” refers to a chemical which, when addedto a LNPR composition, has the effect of discouraging or interferingwith its ingestion, particularly its accidental ingestion by children,by providing an unpleasant, often bitter taste. One preferred bitteringagent is denatonium benzoate (also known as Bitrix®) which can be addedto the LNPR at a concentration of approximately 0.01%-0.02% by weight.

[0065] In the context of the present compositions, the term “microliterquantities” means a volume between 1 and 100 microliters, preferablybetween 5 and 70 microliters, and more preferably between 8 and 60microliters. In preferred embodiments, a volume averaging not more than5, 10, 20, 30, 40, 50, 60, 70, or 100 microliters is applied to a nail,where the standard deviation for replicate applications is not more than0.5. Thus, in the present methods, such quantities of the described nailpolish-lacquer removing compositions can conveniently be applied to anail, so that the applied volume does not exceed an upper limit as justdescribed but is preferably sufficient to coat the entire nail. Themethods and kits thus provide controlled application of small volumes ofremover compositions, typically without the waste associated with use ofdisposable absorbent materials, such as disposable swabs or absorbentfiber balls.

[0066] By “comprising” is meant including, but not limited to, whateverfollows the word “comprising”. Thus, use of the term “comprising”indicates that the listed elements are required or mandatory, but thatother elements are optional and may or may not be present. By“consisting of” is meant including, and limited to, whatever follows thephrase “consisting of”. Thus, the phrase “consisting of” indicates thatthe listed elements are required or mandatory, and that no otherelements may be present. By “consisting essentially of” is meantincluding any elements listed after the phrase, and limited to otherelements that do not interfere with or contribute to the activity oraction specified in the disclosure for the listed elements. Thus, thephrase “consisting essentially of” indicates that the listed elementsare required or mandatory, but that other elements are optional and mayor may not be present depending upon whether or not they affect theactivity or action of the listed elements.

[0067] Other embodiments are within the scope of the invention asdescribed by the following Detailed Description of the PreferredEmbodiments and by the claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0068] As described in the Summary above, the present invention providesa thickened LNPR (liquid nail polish remover) which is based upon thesolvent, gamma butyrolactone (GBL) and/or propylene glycol derivativesolvents which is not irritating or sensitizing to the skin around thefingernail or toenail of a user. In contrast to acetone and ethylacetate-based removers, GBL (on a propylene glycol derivative solvent)is substantially non-volatile, and for reasons which are still unclear,causes little drying of the skin around the nail, and no skin irritationor sensitization upon repeated application, even in the absence of anyhumectant or emollient. The GBL nail lacquer remover is only moderatelytoxic upon ingestion, and has no vapor inhalation hazard. The likelihoodof accidental ingestion (e.g., by children) is reduced by adding abittering agent such as denatonium benzoate, and a solvent thickenerwhich, if the LNPR is packaged in a narrow-necked container, can retardor block the flow of LNPR from the container if the container isinverted or tipped on its side. GBL is water-miscible, biodegradable,and its vapors cause no irritation of the eyes. Even in the absence ofan electrolyte, the remover composition leaves no gummy or stickyresidue after solvent evaporation, or after wiping of the nailpolish/solvent residue from the nail. Furthermore, the removercomposition is especially useful for loosening and removinghard-to-remove so-called “glitter” nail lacquers which contain suspendedflecks of solvent-inert material such as polyester film.

[0069] Accordingly, a thickened nail polish-lacquer removing compositionis provided, having a smooth, substantially non-granular consistency.The composition is substantially non-irritating and non-sensitizing tothe skin surrounding the fingernails and toenails. Upon drying, theresidue of the lacquer-removing composition is water-soluble. Inpreferred embodiments of the nail polish remover composition describedabove, the nail polish removing composition includes:

[0070] (i) from 51% to 99.9%, or preferably 70% to 99.9% by weight ofthe organic solvent, GBL;

[0071] (ii) from 0.1% to 5% by weight of at least one water-solublethickening agent capable of functioning in the absence of a neutralizingagent such as hydroxypropylcellulose (e.g., KLUCEL® H or KLUCEL®G, aso-called “high molecular weight hydroxypropylcellulose” manufactured byHercules, Inc., Aqualon Division, Wilmington, Del.), and which ispresent in an amount effective to produce an absolute kinematicviscosity or a Brookfield viscosity at 20° C. of from 250-10,000 cp;

[0072] (iii) optionally, from 0% to 49% by weight of a co-solvent whichis selected from the group consisting of propylene glycol ethers such aspropylene glycol methyl ether (PM), dipropylene glycol ethers such asdipropylene glycol methyl ether (DPM), propylene glycol ether esterssuch as propylene glycol methyl ether acetate (PMA), dipropylene glycolether esters such as dipropylene glycol methyl ether acetate (DPMA), andmixtures thereof;

[0073] (iv) optionally, from 0% to approximately 20% by weight of ahumectant/diluent which is selected from the group consisting of water,glycerol, propylene glycol, 1,3-butylene glycol and its isomers,sorbitol and combinations thereof;

[0074] (v) optionally, from 0% to approximately 10% by weight of anemollient which is selected from the group consisting of fatty acidesters, mineral oil, silicone oil, lanolin, lanolin derivatives andcombinations thereof.

[0075] Within the above composition ranges specified for compositions ofthis invention, particularly active and effective nail polish removerformulations can include approximately 51% to 99.9% by weight of GBL,varying proportions of PM, PMA or solvent mixtures thereof, and 0.1% to5.0% of a water-soluble thickening agent such as hydroxypropylcellulose.One easily formulated active remover contains approximately 99%-99.5% byweight GBL and 0.5% to 1.0% of KLUCEL® H.

[0076] Also as indicated above, optionally, up to approximately 10% byweight of an emollient can also be included in the nail polish remover.Conventional emollients used in acetone and ethyl acetate removersinclude fatty acid esters, mineral oil, silicone oil, lanolin, lanolinderivatives and combinations thereof. However, the solvents used in thepresent invention are considerably less irritating and depleting of skinoils than either acetone or ethyl acetate, so that addition of anemollient to the formulation may be considered an enhancing feature oroption, rather than a necessity.

[0077] In practicing the present invention, the nail polish lacquerremover composition described above (which can be conveniently providedin a 25-100 ml bottle (or 1-3 fluid ounce) bottle having a smallremovable brush or swab applicator or a sponge applicator), is appliedsparingly to the nail. Typically only 10-50 microliters of thickenedliquid need be brushed or otherwise applied to the fingernail ortoenail. Generally, 10-30 seconds, and typically about 15 seconds areallowed for the remover to soften and dissolve typical polish-lacquersbefore wiping away the residues with a paper tissue or cotton, forexample. As much as 60-120 seconds contact time with the removercomposition may be desirable when stripping off hard to dissolve nailpolish-lacquers such as glitter polishes (see below). The process may berepeated if any polish-lacquer remains on the surface of the nail oraround its perimeter. A user applying the composition to his or hernails will find that it is easy to precisely control coverage ofindividual nails using the thickened liquid and a small applicator.Heavier or lighter application of the remover onto the nail may beappropriate depending upon the particular formulation of nail polish andits ease in being solubilized by the solvent-containing composition.

[0078] Presently invented nail polish lacquer removers are unusual intheir performance in vivo when compared to acetone and ethylacetate-based removers. For example, while the GBL solvent is onlyslightly volatile (vapor pressure= 0.2 mm Hg at 20° C. versus 20 mm Hgfor water), and will persist on the nail for as long as desired, ethylacetate and acetone are highly volatile (80 mm and 200 mm Hgrespectively at 20° C.) and must be replenished frequently when removinga stubborn nail polish. All of these solvents are miscible with waterand have the ability to mobilize or remove fats and oils from hardsurfaces. Indeed, GBL and the propylene glycol-derivative co-solventsare sold industrially as oil-thinning solvents. Yet when GBL and theco-solvents PM, PMA were applied to fingernails and the surrounding skinalongside of acetone and ethyl acetate for between 15 and 60 seconds andthen removed, the GBL, PM and PMA-containing removers were visiblygentler to the skin than comparable acetone and ethyl acetatetreatments. While a single acetone treatment caused immediately anddramatic skin and cuticle surface whitening and drying (moisture andskin oil removal), GBL, PM and PMA treatment produced little effect.While three to four-fold successive acetone applications to thefingernail caused significant skin reddening around the fingernails(erythema), similar applications of GBL, PM and PMA treatments caused nosuch skin reddening.

[0079] The latter in vivo findings are important because erythema is asignificant skin problem associated with acetone-based remover products.Regardless of whether a humectant and/or an emollient were present, GBL,PM and PMA were much gentler to the skin than acetone, causing noirritation or reddening. Concerning exposure of the eyes to solventvapors, acetone has proven to be a significant eye irritant during nailpolish removal. This may be a result of the very volatile nature ofacetone, the significant exposure period and the proximity of the eyesto the fingernails during nail polish removal. By contrast, GBL, PM andPMA solvent vapors caused no eye irritation or eye discomfort during invivo nail polish removal. Given the irritancy of conventionalacetone-based removers to skin and eyes, and given a generallyhealth-conscious public, it is indeed remarkable that acetone-basedremovers have continued to be formulated, and widely used.

[0080] While it was observed that the PM and PMA solvents used alonewere somewhat slower to dissolve dried nail lacquers than acetone andacetone-ethyl acetate removers, GBL solvent was almost as aggressive asacetone. For example, while 100% acetone allowed a doubling coatingthickness of dried lacquer nail polish to be wiped away cleanly within6-8 seconds following solvent contact (depending upon lacquer thicknessand age of the dried lacquer) 100% GBL required approximately 9-11seconds contact time before the lacquer polish could be cleanly removed.However, compared to acetone, Applicant found that the persistence ofGBL-containing coatings owing to their much lower volatility, allowedstubborn dried nail polishes such as glitter polishes (see below) to beremoved much more easily. In fact, one coating of GBL-based LNPR whenallowed to sit 2 minutes on a glitter polish allowed the polish to bewiped off cleanly or rinsed away with water, whereas acetone removerevaporated to dryness within approximately 10 seconds without evensoftening the glitter polish.

[0081] To offset any apparent difference in efficacy between theGBL-based and acetone-based removers, Applicant found that increasingthe solvent coating thickness on the fingernail was helpful infacilitating nail polish removal. Various solvent thickeners were testedfor their abilities to dissolve in GBL. For GBL (with or withoutco-solvents), 0.25% -1.0% by weight hydroxypropylcellulose (such asKLUCEL® H or KLUCEL®G, obtained from Hercules, Inc., Aqualon Division,Wilmington, Del.) was useful.

[0082] In addition, as pointed out in the Summary, if desired thesolvent can be “spiked” by adding a highly volatile co-solvent componentsuch as acetone or ethyl acetate, although other solvents can also beused as additional components. However, the highly volatile co-solventdoes not constitute the principal active solvent for loosening orremoving a nail polish. Thus, the co-solvent component is a secondarysolvent component.

[0083] As stated earlier, the presently invented GBL-based LNPRcompositions demonstrated remarkable efficacy in loosening and removingthe class of nail lacquers known as “glitter” enamels or polishes.Typically, the glitter-type products are distinguished from normal naillacquers by the presence of an abundance of small polyester flakes or“flecks” which are light-reflective and/or light-defracting, producing atinsel-like effect in the polish. Polyester flecks aresolvent-resistant, and together with the clear lacquer vehicle, haveproven to resist both acetone and ethyl acetate-based nail polishremovers.

[0084] For example, one coat of a typical glitter lacquer (Jane brand,product no. 23 VOLTAGE™, produced by Sassaby Cosmetics, Inc., Cardiff bythe Sea, Calif.) was applied to a glass plate surface and air-driedovernight. Approximately 50 seconds of continuous rubbing were requiredfor an acetone-based remover to loosen and remove the coating (using asolvent-saturated Q-tip swab). An ethyl acetate-based remover required65-70 seconds to achieve the same result. These time periods wereessentially 5-10-fold longer than the time required to removeconventional pigmented nail polishes. As a result of the extended timeduration, and the highly volatile nature of acetone and ethyl acetate,it was necessary to apply these removers repeatedly to the glittercoating to achieve its removal. By comparison, only a single applicationof a formulation of the present invention (containing 99.5% by weightGBL and 0.5% KLUCEL®H) was required because the GBL is much lessvolatile than either acetone or ethyl acetate. Shortened solvent contacttimes (as little as 30 seconds) were required for the GBL-based removerto loosen the glitter coating, compared to approximately 60 seconds forethyl acetate-based remover. While conventional acetone and ethylacetate removers evaporate in less than 10 seconds, GBL can persist forseveral minutes on the nail. Both the presence of a thickener (whichallows a heavier coating of remover to be applied to the nail), and thelower volatility of the GBL (compared to acetone), contribute to itspersistence.

[0085] In the interest of further describing the present invention, themost abundant organic solvent molecular species used in the preferredLNPR compositions of the present invention, is gamma-butyrolactone(C₄H₆O₂) or GBL (CAS#96-48-0). It has a remarkably low volatility andhigh flash temperature (209° F.), considering its low molecular weight(86.1). This allows safe handling and shipping of GBL-based LNPRproducts. GBL is miscible with water, allowing convenient wash-off ofresidues on the nail. The optional propylene glycol-derivativeco-solvent molecule used in embodiments of the nail polish lacquerremoving composition of the present invention, contains between 4 and 9carbon atoms and between 2 and 4 oxygen atoms. Thus, at one limit, PMcontains 4 carbon atoms and 2 oxygen atoms, and at the other limit DPMAcontains 9 carbon atoms and 4 oxygen atoms. The vapor pressure of thepropylene glycol solvent or co-solvent is at least 0.05 mm Hg, andpreferably greater than 0.5 mm Hg at 20° C. For example, PM and PMAwhich are preferred co-solvents have vapor pressures, respectively, of8.1 and 3.8 mm Hg at 20° C. While these solvents may be combined withother liquids including diluents and/or humectants and/or emollients,the concentration of organic solvent(s) ranges from approximately 70% to99.9% by weight and preferably from approximately 79% to 99.5% byweight.

[0086] The presence of a thickening agent is also highly preferred forthe functioning of the present invention. First, the thickener allows asubmersible dipping-type applicator, such as a brush or sponge-typeapplicator, to be used to transfer an adequate amount (e.g.,approximately 10-50 microliters) of the viscous or semi-gelled liquidremover from the storage bottle to the nail. The applicator then allowsspreading of the remover over the nail surface. The thickener also helpsin the economy of use of the remover by localizing and maintaining anadequately thick coating of the remover on the nail and cuticle surfacewhere it is needed for softening and dissolving the nail polish.Especially if any volatile co-solvent is added, any solvent spreadingpromotes rapid solvent evaporation and loss of efficacy in dissolvingthe nail polish. The concentration and type of thickener are selected toestablish a viscosity which allows the above-described coatings to beformed on nails. Empirically, the absolute kinematic viscosity (measuredby Canon-Fenske ASTM size 500 viscometer at 20° C.) is preferably in therange of between 250 and 10,000 centipoise (cp), preferably between 100and 10,000 cp. A glycerin viscosity standard was used (1,490 cp at 20°C.).

[0087] One of the benefits of the present invention concerns thesolution of the problem addressed in Miner, U.S. Pat. No. 5,543,085,which was concerned with eliminating gummy and sticky residues oftraditional thickeners (e.g., acrylic acid polymers andhydroxypropylcellulose). These residues, which appear as the solventevaporates from acetone-based nail polish removers, cause the fibers incotton ball applicators to adhere to nails and fingers. Miner reliesupon the addition of an electrolyte to change the gummy characteristicof such residues produced following acetone and ethyl acetate solventtreatment of nail polish-lacquer. In the present invention, it has beendiscovered that gummy and sticky thickener residues need not be formedin the first place, if alternative solvents as described are selected.This is true even when one or more of the traditional thickening agentsof Miner (e.g., hydroxypropylcellulose) is present in the nail polishremover formulation.

[0088] Similarly, one of the principal objects indicated in Bayless,U.S. Pat. No. 5,372,742 is concerned with replacing acetone-ethylacetate and other solvent systems in order to eliminate theirdisagreeable odor, irritancy to the skin and eyes, and drying of thecuticle and nails. Bayless relies upon a non-aqueous cleaningcomposition based upon d-limonene, a terpene. With regard to severalother ingredients which can be added to a mixture of d-limonene, ethyllactate, and cetyl acetate, Bayless mentions the optional use of between10% and 50% by weight of PMA. However, the function of PMA is unclear inthe compositions described in the Bayless patent. In contrast, thepresent compositions utilize a GBL and/or a propylene glycol derivativesolvent as the principal component of the composition. Furthermore,Bayless combines PMA and d-limonene (15%-60% by weight), which rendersthe nail polish remover unusable for the purposes of the presentinvention.

[0089] It is generally known that propylene glycol ether and propyleneglycol ether acetate-based solvents are used as cost-effective diluentsin N-methyl-2-pyrrolidone (NMP)-based commercial paint removers,industrial cleaners, grease removers, and the like. However, Applicantis unaware of any previous suggestion that:

[0090] (i) these propylene glycol-derivative solvents are effective asco-solvents which, together with GBL, provide an effective nail polishremover,

[0091] (ii) GBL and these co-solvents, when combined with traditionalthickeners, e.g., hydroxypropylcellulose, are free of the normaltackiness which accompanies solvent evaporation in the traditionalacetone and ethyl acetate-based products, or that

[0092] (iii) GBL and these co-solvents cause no skin irritation orreddening when compared with the acetone and ethyl acetate-based nailpolish removers.

[0093] One of the propylene glycol ethers (PM, also known as1-methoxy-2-propanol) is an especially effective co-solvent whencombined with GBL, and when thickened with a cellulosic polymer agent,e.g., hydroxypropylcellulose, provide a very useful nail polish remover.While PM is the most volatile of the propylene glycol derivativeco-solvents described in the present invention (vapor pressure= 8.1 mmHg at 20° C.), it is far less volatile than acetone or ethyl acetate,and especially when combined with GBL (vapor pressure=0.2 mm Hg at 20°C.) persists on the nail for a time sufficient to soften the moststubborn of nail lacquers (i.e., persisting for at least 1-3 minutes,depending upon the coating thickness) before evaporating. By contrast,acetone and ethyl acetate are extremely volatile causing a significantinconvenience. They persist only 5-10 seconds on the nail (10-fold lesstime than PM) before they must be replenished. These observations areconsistent with the high vapor pressures of ethyl acetate and acetone atroom temperature (approximately 80 mm and 200 mm Hg which areapproximately 10 and 20-fold greater than that of PM, 8 mm Hg).

[0094] As an additional advantage, GBL as well as all of the propyleneglycol ethers and propylene glycol ether acetates including the PM andPMA solvents are “environmentally friendly”, in the sense that none arelisted on the EPA's HAPS and SARA hazardous chemicals lists, and theyare all biodegradable. PM is especially user-friendly because it is evensubstantially non-irritating to the eyes. GBL has a low rating offlammability (DOT class 1), and PM has a similar flammability to ethanoland acetone (DOT class 3).

[0095] In a panel study, conducted with the cooperation of CosmeticCoatings Corporation (Carlstadt, N.J.), users reported that a GBL-basednail polish remover containing 99.5% by weight GBL and 0.5% by weightKLUCEL H was superior to a conventional acetone-based product because itremoved nail lacquer just as rapidly as acetone but unlike acetone, wasnon-irritating to the skin, did not dry out the nail and cuticle and didnot become sticky like acetone as it was wiped away together withdissolved nail enamel. A convenient means of applying and localizing thesemi-gelled GBL-based liquid remover on the fingernail or toenailwithout wasting any of the remover is by nail polish brush. Accordingly,for consumer use, the thickened remover can be usefully packaged in asmall container, e.g., a one ounce capacity bottle, having a screw capclosure with an integral brush-type applicator.

[0096] While GBL has almost no odor, if PM and/or other volatilepropylene glycol ethers and ether-acetates are added as co-solvents,they have rather pronounced ether and ester-type odors. Any one of anumber of top note fragrances (such as citrus, cherry and other fruitfragrances) can be added as maskers of these odors.

[0097] The described nail remover compositions can be readily preparedor formulated. Those familiar with the formulation of products such asskin care and other cosmetic products readily understand the proceduresand significant preparation parameters involved in formulating andpackaging such products as the present compositions. Preferably thecomponents utilized for these compositions are selected to be suitablefor cosmetic use.

[0098] In general, the preferred solvent components are miscible in eachother and generally are also miscible with water. Thus, preparation of asolvent mixture merely involves combining and mixing those components.

[0099] Most of the specified thickeners are highly soluble or at leastform stable colloids in many of the preferred propylene glycolderivative solvents, and thus can be combined with the solvent andsolubilized by mixing at room temperature or at a slightly elevatedtemperature in order to accelerate the dissolving. Generally this wouldbe performed at atmospheric pressure with the temperature below theboiling point of the solvent, e.g., at a temperature at least 10° C.below the boiling point for a solvent, and more preferably at least 20°C. below the boiling point. In addition, if a thickener is not solublein a base solvent, a co-solvent can be added in which the thickener issoluble. In some cases, a humectant/diluent can act as such aco-solvent. Those skilled in the art will readily recognize suitableco-solvent/thickener selections.

[0100] Humectants commonly used in the preparation of cosmetics aregenerally also miscible in the propylene glycol derivative solvents, andcan therefore by freely added by simple mixing with the solvent.

[0101] Emollients may be of a variety of different types, and havedifferent properties. Those skilled in the art will recognize theappropriate methods for incorporating particular selections ofemollients in the present compositions. In particular, many emollientscan be incorporated by the formation of stable emulsions. Methods forforming such emulsions are well-known in the art and so are notexpressly described herein.

[0102] Since GBL is as much as seven times more costly per pound thanconventional remover solvents (such as acetone and ethyl acetate), thecommercial success and cost-effectiveness of the GBL-based removerdepends upon providing the LNPR in a small quantity (e.g., approximately½-2 ounces), and then using it very effectively and sparingly. Bycomparison, acetone and ethyl acetate are commonly sold in 6-12 ounce orlarger quantities. An economy of usage for GBL is achieved by providingthe LNPR in a thickened form which is easily transferred withoutdripping or spilling, and a solvent applicator device that canrepeatedly deliver microliter quantities, e.g., approximately 10-50microliters, of the LNPR to a nail with little or no waste. One suitableapplicator is a small brush attached to a bottle lid such as thatcurrently provided with printing correction fluids and nail lacquers.Compared to the traditional saturated cotton ball used for applyingconventional acetone LNPRs, a miniature brush applicator allows aslittle as ten microliters to be used in removing lacquer from each nail.With regard to safety, since GBL has moderate oral toxicity, thepresence of a thickener in the LNPR, when combined with packaging theLNPR in a narrow-necked bottle helps to prevent product ingestion bychildren (the thickened product flows slowly if at all through thenarrow-necked opening). A bittering agent is also preferably added tothe LNPR to discourage any ingestion.

[0103] As discussed above, Helioff et al. (U.S. Pat. No. 5,024,779)describe a viscous creamy LNPR which may include GBL. To obtain a smoothtexture, a polymeric thickener consisting of neutralized crosslinkedmaleic anhydride-alkyl vinyl ether copolymer was utilized. Although notexplicitly stated by Helioff et al., it is believed thatcellulose-derived thickeners (such as hydroxypropylcellulose) were foundbe be unsuitable because the cellulosics either fail to dissolve, orform granular rather than creamy thickened solutions in polar organicsolvents such as acetone and GBL. This granular texture is acknowledgedby the manufacturers of hydroxypropylcellulose (KLUCEL®: Physical andChemical Properties; product brochure; Hercules Inc., Aqualon Division,Wilmington, Del.).

[0104] However, cellulosic thickeners have the advantage of maintainingsolution viscosity over a broad pH range (at least between pH 5 and 9)while the copolymer of Helioff et al. must remain at neutral pH tomaintain viscosity. In the present invention, use of a pH-insensitivethickener is desirable because the pH of the LNPR may change over thelifetime of the product as for example, the applicator brush isrepeatedly returned to the LNPR container after applying LNPR tofingernails and toenails.

[0105] To allow the use of a pH-insensitive cellulosic thickener(hydroxypropylcellulose) in the present invention, a method wasdeveloped to convert KLUCEL® (after dispersal in GBL) from anunacceptable granular suspension to a creamy-smooth, thickened solution.The method utilized, which involves shearing and filtering the granularsuspension, is as follows: KLUCEL® type H was dispersed into GBL liquidby propeller stirrer (1% by weight final concentration). Afterincubating the particle suspension for approximately 4-6 hours at 23degrees Celcius, the liquid appeared uniform but highly granular. Thesuspension was transferred to a Hockmeyer blade-type high speeddisperser. The disperser was run at 1500 rpm for 1 hour and finally 5000rpm for 0.5 hours. This treatment, which would be expected to shearcellulose polymer chains and substantially reduce solution viscosity,eliminated most of the suspension's granularity while surprisingly, notsignificantly reducing the solution viscosity. To eliminate remaininggranularity, the solution was mesh-filtered through a polyester organzacloth material. Final KLUCEL® H concentration was adjusted to betweenapproximately 0.25%-1.0% by weight (preferably 0.25% or 0.5% by weight)by addition of GBL and/or other components constituting the LNPR.Including other viscosity grades and types of cellulosic thickeners, theoverall cellulose concentration can range between 0.1% and 5% by weight.In any event, the absolute kinematic viscosity of the LNPR measured bythe Brookfield or Canon-Fenske method at 20° C. is preferably between250 cp and 10,000 cp. As indicated above, other methods for eliminatingthe granularity of a cellulosic thickener can involve centrifugation,e.g., centrifugation at approximately 5,000×g. As recognized by thoseskilled in the art, the time and/or speed of centrifugation can bereadily adjusted to provide beneficial or optimal separation.

[0106] In addition, it was observed that lower molecular weightthickener, e.g., KLUCEL®G, resulted in significantly less or nogranularity or initial dissolving approximately twice as much KLUCEL®G(avg, molecular mass=330 kD) was required to produce equivalentthickening as compared to KLUCEL® H (avg. molecular mass=1.15 Mda).Thus, suitable selection of the thickener may eliminate the need toeliminate granularity.

[0107] The effectiveness of the presently invented LNPR derives fromcertain chemical and physical properties of GBL which distinguish itfrom nearly all other nail polish remover solvents with the possibleexception of N-methylpyrrolidone (abbreviated NMP). GBL and NMP arehighly aggressive paint-dissolving solvents which, unlike acetone, ethylacetate, methylene chloride and the like, have unusually low vaporpressures and volatilities. Applicant has found that the combination ofsolvent potency and low volatility, not only allows GBL to rapidlysoften and dissolve nail lacquers, but then allows the lacquer residueto be wiped away cleanly without leaving a sticky lacquer residue. Bycontrast, the high volatility of acetone, ethyl acetate and many othersolvents leads to premature solvent evaporation, resulting in a stickynail lacquer residue being left on the nail. Then, cotton applicatorfibers inconveniently adhere to such sticky residues.

[0108] According to the present invention, GBL is preferred over NMP,acetone and other solvents as a LNPR solvent for other reasons as well;Whereas NMP and acetone are moderate skin irritants, causing redness,cracking and blistering of the skin around the nails after repeatedcontact, GBL has been found to cause no such skin irritation afterrepeated application (in spite of it causing eye irritation). Aside fromthe cost advantage of acetone, considering the irritancy of acetone andits inconvenience of use due to its extreme volatility, it is surprisingthat acetone has been the preferred LNPR for so many decades. There arealso environmental issues related to the use and disposal of many otherorganic solvents. For example, under the U.S. Environmental ProtectionAgency, NMP is a SARA Title III Section 313-listed polluting solvent.GBL, on the other hand, is environmentally “friendly” and SARA-unlisted,being readily hydrolyzed to hydroxybutyric acid, a natural product foundin human urine.

[0109] As a LNPR solvent, GBL is also preferred over the propyleneglycol ethers and propylene glycol ether ester solvents describedrecently by Applicant in co-pending U.S. patent application Ser. No.09/144,189. This is because GBL is more potent and acts considerablyfaster to soften and remove conventional nail lacquers, particularlylacquers which have dried and hardened on the nail for between severaldays and one week. In this regard, experiments indicate that a singleapplication of GBL-based LNPR (90%-99.5% by weight GBL plus thickener)can dissolve a hardened nail lacquer at least twice as rapidly as PM(and approximately the same speed as continuous acetone treatment).

[0110] In spite of the many advantageous properties of GBL, Applicantbelieves that several problems have prevented commercialization of aGBL-based LNPR. Identifying and solving these problems constitute animportant part of the present invention. The first obstacle to using GBLas a major component in a LNPR formulation is cost. Although GBL wasmentioned in Helioff et al. and Day as a possible chemically effectiveLNPR solvent, its current cost of approximately $2.00 per pound haslargely ruled it out as a commercially competitive LNPR ingredient, whencompared to acetone at $0.28 per pound, and ethyl acetate at $0.35-0.40per pound (bulk prices). Second, the thickening systems for a GBL-basedLNPR as described by Helioff et al. and Day, become unworkable if asignificant pH change occurs in the solvent, i.e., viscosity would belost. Third, the formulation of Helioff et al., yields a water-insolublecoating on the nail, requiring soap and water for its removal. Fourth,GBL has been identified as a potential health hazard, inducingreversible coma if orally ingested in substantial quantity (gammabutyrolactone-Material Safety Data Sheet, 1998, Arco Chemical Company,Newtown Square, Pa.). As a result of this child-safety hazard, Applicantwas advised by the Arco Chemical Company, that GBL is not favored foruse in a consumer product.

[0111] Several practical and cost-effective remedies have now been foundfor the above GBL-related problems. These remedies, in brief, involve:

[0112] (a) Providing a re-usable microapplicator which facilitatessparing application of the LNPR to individual nails, thereby reducingthe amount of LNPR and the cost of GBL solvent required for removingpolish from each nail. With the applicator described, a container hasbeen tested with as little as one ounce of GBL-based LNPR which isadequate for removing nail lacquer from a set of ten fingernails on50-100 separate occasions, using only between 10 and 50 microliters ofthe LNPR per nail.

[0113] (b) Utilizing a mannose-necked container with a limited capacity,e.g., not more than 25, 30, 50, 60, 80, or 100 ml. (or 1, 2, or 3 fluidounces).

[0114] (c) Modifying the composition of a prior art GBL-containing LNPRby employing a pH-insensitive thickener. This thickener allows repeateduse of the microapplicator (see A above) without danger of viscosityloss, even when a pH change occurs in the LNPR (e.g., with entry ofcontaminants into the LNPR via the micro-applicator). Unlike thethickener of Helioff et al., the selected thickener is water-soluble toallow convenient water rinsing of the nails (no soap required) followingnail polish removal.

[0115] (d) Introducing a bittering agent such as Bitrix® which, togetherwith the thickener, reduces the risk of GBL ingestion by children.Compared with commercially packaged quantities of conventional LNPRs(6-12 ounces), the reduced quantity of GBL used in a packaged LNPR ofthe present invention (typically 1 ounce) also reduces the overalltoxicity risk to children.

[0116] The following description is intended to provide a more detailedexplanation of these remedies. Item (a) is discussed first. In theabsence of any information on how the creamy nail polish of Helioff etal., U.S. Pat. No. 5,024,779 is to be applied to the nail, theconventional method of applying a LNPR and removing the lacquer isassumed, i.e., by use of a cotton ball. In this case, a quantity ofapproximately 1-2 grams of LNPR is instilled into a cotton ball or wadof toilet paper, which is then used to cleanse one or two nails at atime. In the process of removing lacquer from ten fingernails, betweenfive and ten grams of LNPR may be utilized. Based upon the current priceof chemicals, ten grams of a GBL-based remover @ $2.00 per pound wouldcost approximately 4 cents. However, to be competitive with theseven-fold lower cost of an acetone-based remover, Applicant believesthat the “cost per use” (defined as the bulk price of chemicals requiredto clean 10 nails) for a GBL-based LNPR must be reduced from 4 cents toapproximately ½ cent. This cost reduction would not be possible usingthe conventional method of applying the LNPR using an absorbent paper orcotton. However, if approximately 50 microliters of LNPR were sufficientfor removal of lacquer from each nail, the requisite cost-savings couldbe obtained. Then, 1 fluid ounce of LNPR would be sufficient forremoving lacquer from over 500 nails. By using a small brush or other“zero-waste” application method with a GBL-based LNPR to a nail, it isestimated that 5 to 10-fold less LNPR could be applied (than the amountof acetone which is currently used with a cotton ball applicator) toremove nail polish from a fingernail, and a GBL-based remover could bepriced competitively with a conventional acetone or ethyl acetate-basedremover.

[0117] The efficacy of applying varying amounts of thickened LNPRdirectly onto the fingernail has been tested. Calibrated volumes of theLNPR were dispensed from a micropipet instrument (Rainin InstrumentCompany, Woburn, Mass.; Pipetman™ P250) onto a fingernail. In fact, itwas determined that a volume of between 10 and 50 microliters of theLNPR containing 99%-99.5% by weight GBL and 0.5%-1.0% KLUCEL™ Hthickener (see below) was sufficient for coating a fingernail andremoving nail polish. As a practical means of applying and spreadingthese small volumes of thickened LNPR uniformly over a fingernail ortoenail, Applicant has employed a conventional nail lacquer applicatorbrush. Such brushes, which are typically incorporated into the lidswhich cover nail polish bottles, have bristles which are approximately¼-½ inch long. As with nail lacquer brushes, the brush (which isattached via a plastic rod to the lower inside surface of the screw-caplid) is dipped into the GBL-based LNPR and used to “paint” the thickenedliquid onto the nail. This simple and cost-effective applicator isre-usable, and as an integral portion of the lid, rests submerged in theLNPR, ready for use, within a 1-2 or 1-3 fluid ounce capacity container.In fact, any small brush, swab or equivalent applicator can be used todip and transfer a small amount of the thickened LNPR from a containerto a nail.

[0118] With regard to item (c) above, the thickener described by Helioffet al. would not be suitable for the present invention because of itssusceptibility to changes in the pH of the LNPR. That is, repeated entryof the microapplicator [described in (a) above] into the LNPR aftercontact with the nails and skin is expected to introduce acidic or basiccontaminants which will change the pH of the LNPR, causing a loss ofviscosity. Thus, the composition of the existing GBL-based LNPR mustinclude a pH-insensitive thickener to avoid viscosity loss in the LNPRdue to such pH changes. In addition, the residue resulting fromair-drying of the thickened GBL-based LNPR described herein, isconveniently water-soluble, rather than requiring soap or detergent forits removal as described by Helioff et al.

[0119] With regard to (d) above, the presently invented GBL-based LNPRproduct is formulated, packaged and sized to reduce the risk of, andfrom, accidental ingestion by children. A chemical bittering agent isadded to the product to cause oral rejection of the LNPR if it istasted. The thickened LNPR product is also preferably packaged in anarrow-necked container, reducing or preventing easy child-access to theproduct inside the container. Finally, the small volume of containers(1-2 ounces) used to hold the LNPR, limits the overall potential harmfrom accidental product ingestion, relative to the common use of 8 ounceLNPR containers.

[0120] Concerning the prior art use of GBL solvent in a LNPR (see U.S.Pat. No. 5,024,779), Helioff et al. describe a thickened LNPR whoseactive solvent is preferably acetone, but may also include methyl ethylketone, ethyl acetate, gamma butyrolactone, and mixtures thereof.Helioff et al. require that hydrolyzed, neutralized maleicanhydride-alkyl vinyl ether copolymer cross-linked via apolyethylenenically unsaturated compound is used as the thickener forachieving a smooth cream-like texture. Use of this thickener requiresthat a pH-neutralizing agent be present in the formulation to maintain agelled state. A dried coating of the thickener is water-insoluble butcan be removed with soap and water. The thickeners used in Day alsorequired use of a neutralizer, indeed a particular neutralizer wasrequired On the other hand, cellulose-derived hydrocolloid thickenerssuch as hydroxypropylcellulose acetate were previously used for acetoneand ethyl acetate LNPRs (e.g., Minton et al., U.S. Pat. No. 4,197,212).It is likely that the granular consistency of cellulosic thickenersdispersed in organic solvents (such as acetone, ethyl acetate and GBL)was found undesirable by Helioff et al. who wished to obtain “acream-like consistency.” This solvent granularity has also been reportedelsewhere (“KLUCEL®-Physical and Chemical Properties”, brochure #250-2Erevised 4-97, Hercules, Inc. Aqualon Division, Wilmington, Del.).

[0121] The thickened LNPR of the present invention is very differentfrom that described by Helioff et al. For example, the selection andphysical processing of thickening agent, the compatability of thickenerwith changes in pH within the LNPR, the use of a narrow-necked containerfor flow restriction and thereby child safety (to minimize child contactand accidental ingestion of the remover even when it is in use), and theuse of a micro-applicator for conserving the product are unique to thepresent invention. These features are important for making the productsafe, effective and cost-efficient. Unlike acetone-based removers, thepresent remover is non-irritating, non-sensitizing, and substantiallynon-desiccating to the skin surrounding the nail. Furthermore, theGBL-based nail polish remover is safer to store, handle and ship than anacetone or ethyl acetate-based product because GBL is substantiallynon-flammable owing to its high flash point (209° F.). While theflammability problem of LNPRs has been addressed previously in U.S. Pat.No. 4,543,206 by Adams, there is a toxicity issue and environmentalpollution problem associated with use of his LNPR (based upon methylenechloride).

[0122] The following examples illustrate the in vitro effectiveness ofpropylene glycol-derivative LNPRs as well as GBL-based LNPRs insoftening and dissolving commercial nail polishes.

EXAMPLE 1

[0123] This example shows that a variety of propylene glycol ethers andpropylene glycol ester ethers, with and without modest dilution bywater, can rapidly soften and release a single coating of conventionalnail polish lacquer (L'Oreal Nail Enamel,#395, L'Oreal Canada, Inc.,Montreal, Canada). An in vitro test which was developed to monitor therelative efficacy of different solvents and dilutions thereof is hereindescribed. Approximately one hundred 1 cm² round spot-coatings of theRevlon nail enamel product were applied by brush to a glass sheet andair-dried for one week before solvent removal experiments wereconducted. One commercial acetone-based, and one commercial ethylacetate-based nail polish remover [CVS brand “Polish Remover-RegularFormula” (containing acetone, water, glycerin and gelatin), and also CVSbrand “Nail Polish Remover-Non-Acetone” (containing ethyl acetate,alcohol, castor oil, butyl stearate, and other minor ingredients) bothproducts being distributed by CVS Inc., Woonsocket, R.I.] wererespectively used as “control” nail polish remover solvents. Thesecontrols helped to determine how rapidly the presently describedsolvents could loosen a nail polish-lacquer, compared to conventionalsolvent-based removers. For each trial, a solvent was applied to a nailpolish spot coating using a conventional pipe cleaner (a tuftedfabric-coated wire which was saturated with the solvent contained in aglass test tube). Each pipe cleaner had been bent into an L-shape priorto solvent-saturation, such that the bottom of the L presented a flat, 1centimeter long segment to contact the nail polish spot-coating. Thesolvent-saturated pipe cleaner was gently and continuously rubbed backand forth (approximately one back and forth cycle per second) over thespot coating until the colored nail polish spot had been removed. Usinga stop watch, and observing the point in time at which the opaque nailpolish visually cleared, it was possible to determine, with goodreproducibility, the number seconds of solvent contact with rubbing,required for removal of the nail polish. The time range (in seconds)required to remove each of four essentially identical spot coatings isgiven. TABLE I LACQUER REMOVAL SOLVENT (weight %) (seconds) Solvent CASNo. CVS acetone remover (control) 3.0-3.5 67-64-1 CVS ethyl acetateremover (control) 3.0-3.5 141-78-6 100% PM 3.5-4.0 107-98-2  90% PM +10% H₂O 6-7  80% PM + 20% H₂O  9-10  70% PM + 30% H₂O 30-34 100% PMA3.0-3.5 108-65-6  90% PMA + 10% H₂O 3.5-4.0 100% DPM 10-12 34590-94-8100% DPMA  7-8 88917-22-0 100% PE   5-5.5 52125-53-8  90% PE + 10% H₂O7-8  80% PE + 20% H₂O  9-10 100% PEA 4-5 98516-30-4 100% PTB 22-2557018-52-7 100% DPNB 25-28 29911-28-2

[0124] Results and Discussion: The PM and PMA solvents were nearly asrapid as acetone and commercial ethyl acetate-based removers in removinga single coating of dried nail polish from a glass plate. The PEA and PEwere the next most aggressive, followed by DPMA and DPM. As the overallmolecular weight and the size of the ether-linked alkyl side groupincreased, the time required to loosen and remove the nail polishincreased. This may be due to larger solvent molecules having moredifficulty penetrating a nail lacquer barrier than smaller molecules,within a given solvent family, i.e., the propylene glycol ether family.As anticipated, dilution of the solvents by water, substantially reducedtheir rate of loosening and removing a lacquer nail polish.Interestingly, 10% by weight of water reduced the effectiveness of PMsomewhat more than it affected PMA. The addition of 5%-10% water to PMAallows convenient thickening of this solvent using a cellulosicthickener such as hydroxypropylcellulose.

EXAMPLE 2

[0125] This example shows that gamma butyrolactone (GBL) can rapidlysoften and dissolve a double coating of conventional nail polish lacquer(L'Oreal Nail Enamel,#395, L'Oreal Canada, Inc., Montreal, Canada). Thesame test described in Example 1 was used, except that two coatings ofthe lacquer were applied to each spot location and dried for one week.GBL, either alone or together with a co-solvent (PM), was thickened with0.5% by weight hydroxypropylcellulose (KLUCEL® H), and utilized in thisexperiment. Removers described in Example 1 were also utilized. TABLE 2LACQUER REMOVAL Solvent SOLVENT (weight %) (seconds) CAS No. CVS acetoneremover (control)   6-7.5 67-64-1 CVS ethyl acetate remover (control)7-9 141-78-6 99.5% GBL + 0.5% KLUCEL ® H  8-10 96-48-0 89.5% GBL + 10%PM + 0.5% KLUCEL ® H  9-11 79.5% GBL + 20% PM + 0.5% KLUCEL ® H 12-14100% PM 15-18 107-98-2 100% PMA 14-17 108-65-6

[0126] Results and Discussion: Comparing these results with those inExample 1, the addition of a second coating of nail lacquer nearlydoubled the time required for acetone and ethyl acetate to dissolve thecoatings. While the GBL solvent was nearly as effective as commercialacetone and ethyl acetate-based removers for removing the double coatingof dried nail polish from a glass plate, the PM and PMA removersrequired additional time.

[0127] All patents and publications mentioned in the specification areindicative of the levels of skill of those skilled in the art to whichthe invention pertains. All references cited in this disclosure areincorporated by reference to the same extent as if each reference hadbeen incorporated by reference in its entirety individually.

[0128] One skilled in the art would readily appreciate that the presentinvention is well adapted to carry out the objects and obtain the endsand advantages mentioned, as well as those inherent therein. The gammabutyrolactone and propylene glycol derivative solvent compounds and theother particular described components of the compositions, and themethods described herein as presently representative of preferredembodiments are exemplary and are not intended as limitations on thescope of the invention. Changes therein and other uses will occur tothose skilled in the art, which are encompassed within the spirit of theinvention, are defined by the scope of the claims.

[0129] It will be readily apparent to one skilled in the art thatvarying substitutions and modifications may be made to the inventiondisclosed herein without departing from the scope and spirit of theinvention. For example, use of other polyethylene glycol derivativesolvents or small amounts of co-solvents are all within the scope of thepresent invention. Thus, such additional embodiments are within thescope of the present invention and the following claims.

[0130] The invention illustratively described herein suitably may bepracticed in the absence of any element or elements, limitation orlimitations which is not specifically disclosed herein. Thus, forexample, in each instance herein any of the terms “comprising”,“consisting essentially of” and “consisting of” may be replaced witheither of the other two terms. The terms and expressions which have beenemployed are used as terms of description and not of limitation, andthere is no intention that in the use of such terms and expressions ofexcluding any equivalents of the features shown and described orportions thereof, but it is recognized that various modifications arepossible within the scope of the invention claimed. Thus, it should beunderstood that although the present invention has been specificallydisclosed by preferred embodiments and optional features, modificationand variation of the concepts herein disclosed may be resorted to bythose skilled in the art, and that such modifications and variations areconsidered to be within the scope of this invention as defined by theappended claims.

[0131] In addition, where features or aspects of the invention aredescribed in terms of Markush groups or other grouping of alternatives,those skilled in the art will recognize that the invention is alsothereby described in terms of any individual member or subgroup ofmembers of the Markush group or other group.

[0132] Thus, additional embodiments are within the scope of theinvention and within the following claims

What we claim is:
 1. A safety-enhanced packaged liquid nailpolish-lacquer removing composition, comprising a nail polish-lacquerremoving solution which is non-irritating and non-sensitizing to theskin comprising between 51% and 100% by weight of thickenedbutyrolactone solvent, wherein said solution is packaged in anarrow-necked container, said narrow neck serving to retard or block theflow of said solution when said container is tipped on its side orinverted, and wherein a maximum of 100 ml of said solution is in saidcontainer, and a reusable applicator device for applying microliterquantities of said solution to each nail.
 2. The composition of claim 1, wherein a maximum of 30 ml of said solution is in said container. 3.The composition of claim 1 , wherein said applicator device is selectedfrom the group consisting of an applicator brush, porous foam swab orpad, hollow tube, eye dropper, dip stick or combination thereof.
 4. Thecomposition of claim 1 , wherein said reusable applicator device isattached to a lid which covers said container.
 5. The composition ofclaim 1 , wherein said solution further comprises at least onethickening agent present in an amount effective to produce an absolutekinematic viscosity at 20° C. of from 250-10,000 cp.
 6. The compositionof claim 5 , wherein said thickening agent functions in the absence of aneutralizing agent.
 7. The composition of claim 6 , further comprising abittering agent.
 8. A liquid nail polish-lacquer removing compositionhaving a thickened, and substantially non-granular consistency, whereinsaid composition is substantially non-irritating, and non-sensitizing tothe skin surrounding the fingernails and toenails, and wherein theresidue of said composition upon drying, can be rinsed away with water,said composition comprising: (i) from 51% to 99.9% by weight ofbutyrolactone organic solvent; (ii) from 0.1% to 5% by weight of atleast one pH stable thickening agent present in an amount effective toproduce an absolute kinematic viscosity at 20° C. of from 250-10,000 cp;(iii) optionally, from 0% to approximately 49% of a propyleneglycol-derivative co-solvent compound having between 4 and 9 carbonatoms and between 2 and 4 oxygen atoms per molecule, wherein saidcompound is selected from the group consisting of propylene glycolethers, dipropylene glycol ethers, propylene glycol ether esters,dipropylene glycol ether esters and combinations thereof; (iv)optionally, from 0% to approximately 20% by weight of ahumectant/diluent which is selected from the group consisting of water,glycerol, propylene glycol, 1,3-butylene glycol and its isomers,sorbitol and combinations thereof; and (v) optionally, from 0% toapproximately 10% by weight of an emollient which is selected from thegroup consisting of fatty acid esters, mineral oil, silicone oil,lanolin, lanolin derivatives and combinations thereof.
 9. The nailpolish-lacquer removing composition of claim 8 packaged in anarrow-necked container, wherein the narrow neck serves to retard orblock the flow of said composition when said container is tipped on itsside or inverted, and thereby reduce the possibility of ingestion bychildren.
 10. The nail polish-lacquer removing composition of claim 8 ,wherein said composition further contains an effective concentration ofa bittering agent to reduce the possibility of ingestion by children.11. The nail polish-lacquer removing composition of claim 8 , whereinsaid composition is packaged in a container containing not more thanthree fluid ounces of said composition, wherein the limited quantity ofsaid composition in said container serves to limit the potentialingestion hazard to a child.
 12. The nail polish-lacquer removingcomposition of claim 11 , wherein said container comprises a reusableapplicator device for applying microliter quantities of said compositionto each nail.
 13. The nail polish-lacquer removing composition of claim12 , wherein said microliter quantities of said composition are between10 and 100 microliters per nail.
 14. The nail polish-lacquer removingcomposition of claim 12 , wherein said container comprises a reusableapplicator device selected from the group consisting of an applicatorbrush, porous foam swab or pad, hollow tube, eye dropper, dip stick orcombination thereof.
 15. The nail polish-lacquer removing composition ofclaim 14 , wherein said reusable applicator device is attached to a lidwhich covers said container.
 16. The nail polish-lacquer removingcomposition of claim 8 , wherein said composition allows fingernails andtoenails to remain substantially free of any sticky residue during thelacquer-removal process, without addition of any electrolyte to saidcomposition.
 17. The nail polish-lacquer removing composition of claim 8, wherein the vapors from said solvent are substantially non-irritatingto the eyes.
 18. The nail polish-lacquer removing composition of claim 8, wherein said propylene glycol-derivative co-solvent is selected fromthe group consisting of propylene glycol methyl ether (PM;1-methoxy-2-propanol, CAS No. 107-98-2), propylene glycol methyl etheracetate (PMA; 1-methoxy-2-propanol acetate, CAS No. 108-65-6),dipropylene glycol monomethyl ether (DPM; CAS No. 34590-94-8),dipropylene glycol methyl ether acetate (DPMA; CAS No. 88917-22-0),propylene glycol ethyl ether (PE; CAS No. 52125-53-8), propylene glycolethyl ether acetate (PEA; CAS No. 98516-30-4), propylene glycol n-propylether (PNP; CAS No. 1569-01-3), propylene glycol t-butyl ether (PTB; CASNo. 57018-52-7), propylene glycol n-butyl ether (PNB; CAS No.5131-66-8), and dipropylene glycol n-propyl ether (DPNP, CAS No.29911-27-1).
 19. The nail polish-lacquer removing composition of claim 8, wherein said thickening agent is selected from the group consisting ofcellulose derivatives, natural gums, inorganic thickeners, and synthetichomopolymers and copolymers having from 1 to 30 carbon atoms per monomerunit.
 20. The nail polish-lacquer removing composition of claim 19 ,wherein said thickening agent is a cellulose derivative selected fromthe group consisting of hydroxycellulose, hydroxyalkylcellulose, andcarboxymethylcelluose.
 21. The nail polish-lacquer removing compositionof claim 20 , wherein said hydroxyalkylcellulose thickening agent isselected from the group consisting of hydroxyethylcellulose,hydroxypropylcellulose, and hydroxypropylmethylcellulose.
 22. The nailpolish-lacquer removing composition of claim 19 , wherein saidthickening agent is a synthetic homopolymer or copolymer selected fromthe group consisting of polyacrylic acid esters, polymethacrylic acidesters, polyvinylacetate, and polyvinylpyrrolidone.
 23. The nailpolish-lacquer removing composition of claim 19 , wherein saidthickening agent is a natural gum selected from the group consisting ofacacia, alginate, carrageenan, guar, karaya, pectin, tragacanth, andxanthan.
 24. The nail polish-lacquer removing composition of claim 19 ,wherein said thickening agent is an inorganic thickener selected fromthe group consisting of silicas and clays.
 25. The nail polish-lacquerremoving composition of claim 8 , wherein said thickening agent whichcan function in the absence of a neutralizing agent, can maintain saidviscosity with changes in pH, wherein said changes in pH may occur insaid composition after a reusable applicator device is repeatedly placedinto said composition during nail polish-lacquer removal operations. 26.A nail polish-lacquer removing composition comprising from 51% to 99.9%of GBL; and at least one thickening agent which is present in an amounteffective to produce an absolute kinematic viscosity at 20° C. of from250 to 10,000 cp, wherein said thickening agent is not neutralizedcrosslinked maleic anhydride-alkyl vinyl ether copolymer gel or aneutralized acrylic acid polymer neutralized with N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylaminediamine and2-ethyl-N-(2-ethylhexyl-1-hexamine.
 27. A liquid nail polish-lacquerremoving composition which is substantially non-irritating andnon-sensitizing to the skin surrounding the fingernails and toenails,wherein said composition comprises between 51% and 100% by weight ofbutyrolactone solvent, which composition is packaged in a containercomprising a reusable applicator device for applying microliterquantities of said composition to each nail.
 28. The nail polish-lacquerremoving composition of claim 27 , wherein said applicator device isselected from the group consisting of an applicator brush, porous foamswab or pad, hollow tube, eye dropper, dip stick or combination thereof.29. The nail polish-lacquer removing composition of claim 27 , whereinsaid reusable applicator device is attached to a lid which covers saidcontainer.
 30. The nail polish-lacquer removing composition of claim 27, wherein said composition further comprises at least one thickeningagent capable of functioning in the absence of a neutralizing agent, andwhich is present in an amount effective to produce an absolute kinematicviscosity at 20° C. of from 250-10,000 cp;
 31. The nail polish-lacquerremoving composition of claim 30 , wherein said composition is packagedin a narrow-necked container, wherein the narrow neck serves to retardor block the flow of said composition when said container is tipped onits side or inverted, and thereby reduce the possibility of ingestion bychildren.
 32. A nail polish-lacquer-removing composition comprising abutyrolactone solvent or a propylene glycol derivative solvent orcombinations thereof, wherein said butyrolactone and said propyleneglycol derivative solvents together comprise from 51% to 99.9% by weightof said total nail polish lacquer-removing composition; and at least onepH stable thickening agent present in an amount effective to produce anabsolute kinematic viscosity at 20° C. or from 250 to 10,000 cp.
 33. Thecomposition of claim 32 , wherein said, said butyrolactone and saidpropylene glycol derivative solvents together comprise from 80% to 99.9%of said total nail polish lacquer-removing composition.
 34. Thecomposition of claim 32 , wherein the weight percentage of saidbutyrolactone solvent is greater than the weight percentage of saidpropylene glycol derivative solvent.
 35. A method of removing a nailpolish-lacquer coating from a fingernail or toenail without causingirritation of the skin surrounding the nail, comprising the steps of:applying the composition of claim 8 to said coating on said fingernailor toenail; allowing the coated fingernail or toenail and saidcomposition to remain in contact for a time sufficient to loosen saidcoating from said fingernail or toenail, and separating and removingsaid coating and said composition from said fingernail or toenail.
 36. Amethod of conveniently removing a glitter-type nail polish-lacquercoating from a fingernail or toenail without causing irritation of theskin surrounding the nail, comprising the steps of: applying thecomposition of claim 8 to said coating on said fingernail or toenail;allowing the coated fingernail or toenail and said composition to remainin contact for a time sufficient to loosen said coating from saidfingernail or toenail, and separating and removing said coating and saidcomposition from said fingernail or toenail.
 37. A method of treating agranular suspension of between 0.1% and 5% by weighthydroxypropylcellulose contained in a liquid comprising between 51% and99.9% by weight butyrolactones, to produce a smooth-textured thickenedsolution, comprising removing a sufficient proportion of granularmaterial from said suspension to provide said smooth-textured thickenedsolution.
 38. The method of claim 37 , wherein said removing comprisesshearing and filtering said granular suspension.
 39. The method of claim37 , wherein said removing comprises centrifuging said granularsuspension.
 40. The method of claim 37 , wherein said removing comprisesshearing, filtering, centrifuging, or combinations thereof said granularsuspension.